1 Field of the Invention
This invention relates to a monoclonal antibody against ganglioside GD.sub.1a, cells capable of producing the antibody, and a reagent containing the antibody and being suitable for use in the detection or quantification of ganglioside GD.sub.1a.
2Description of the Related Art
Although various monoclonal antibodies against gangliosides have been proposed, no monoclonal antibody against GDIa has heretofore been known.
Glycolipids are biosubstances which have attracted attention, especially in the investigation of the development, differentiation and canceration of cells. Among such glycolipids, glycosphingolipids containing sialic acid are collectively called "gangliosides". GD.sub.1a (hereinafter called merely "GD.sub.1a ") is one of these gangliosides.
GD.sub.1a is a substance abundant in human and various animals, especially in the nervous system tissues. The composition of gangliosides in the blood of a cancer patient or a patient with systematic lupus erythematosus (SLE), an autoimmune disease, has been reported to be different significantly from that of healthy people [Journal of Biochemistry, 98, 843 (1985)]. Namely, gangliosides which are contained in the form of immune complexes in the blood are principally composed of GM.sub.3 in the case of healthy people, while GM.sub.3 is practically unobserved in cancer or SLE patients. Instead, GM.sub.1 and GD.sub.1a are contained as the principal gangliosides. It is hence possible to estimate whether an individual is suffering from a cancer or SLE, provided the GD.sub.1a in his blood can be quantified precisely.
Like GM.sub.1 and the like, GD.sub.1a is also a principal ganglioside of the nervous system. When one or more diseases are developed due to an organic injury of the nervous system, such as demyelination, GD.sub.1a is hence believed to move into the blood or cerebrospinal fluid. Accordingly, it is also possible to estimate from the measurement of the concentration of GD.sub.1a in the blood or cerebrospinal fluid whether one is suffering from a disease of the nervous system due to an organic injury.
As methods for the quantification, identification or purification of GD.sub.1a, immunological methods making use of an antibody specific to GD.sub.1a have been found to be useful, in addition to conventional chemical and biochemical methods. As antibodies against GD.sub.1a, those derived from an antiserum, which are obtained by immunizing a rabbit with GD.sub.1a together with a suitable carrier and an immunoadjuvant, have conventionally been used. They are so-called polyclonal antibodies, so that their specificity is not always uniform among production lots or depending upon individual animals employed for the immunization. It has hence been desired to obtain a monoclonal antibody which is free of such drawbacks.